A Japanese government panel on earthquakes says there is a high probability that active faults off the Noto Peninsula played a part in the seismic activity that resulted in a series of quakes that started on New Year's Day.

Experts of the Earthquake Research Committee met on Monday to analyze observation data of seismic activity in and around the peninsula in central Japan.

They agreed on the high probability that the confirmed faults stretching from west to north or northeast off the peninsula were involved in the seismic activity that caused the tremors.

The experts added that active faults off the west coast of Sado Island in the Sea of Japan may also have been involved.

The committee had not analyzed data of the offshore faults to calculate the likelihood of them causing a major quake. Previously, it focused mainly on terrestrial active faults.

It says the number of tremors has decreased after January 1, but seismic activity in the region remains active.

The experts say people should stay on alert for strong tremors with an intensity of upper five or higher on the Japanese scale of zero to seven for the next two or three weeks.

They cited a magnitude 7.7-quake that struck off the Sea of Japan coast of Akita Prefecture in northern Japan in 1983 and another 7.8-quake that occurred off southwestern Hokkaido in 1993.

Quakes of magnitudes 6-to-7 class were still recorded about one month after the major ones.

University of Tokyo Professor Emeritus Hirata Naoshi, who heads the government's panel, said that people need to stay vigilant as it is still uncertain whether or not there could be a quake larger than that on New Year's Day.